Here's a dumb question. Why cant you print a p2 halve laying on its side this way all the rib details would be facing up and most of the support scaffolding would be on the inside?
That's actually a really good question, and I had to learn the answer the hard way. It has to do with the way 3D printing works, the different ways to orient the model for better results, and the cost of printing the entire thing in something like the Extreme Detail Plastic at Shapeways as opposed to just the parts that need that level of detail. If money were no object, I would just do the shells as one piece in that plastic. But that would cost a fortune.
3D printing on the Makerbot works by first slicing the model like a salami in software, and then depositing each slice as a layer of molten plastic. The thinner the slices, the better the resolution of the model, but the more it costs in printing time. The Makerbot Replicator 2 can make the slices as thin as 0.1mm (or maybe even 0.05mm, but I'm not sure), but that would take about 16 hours to print one shell, so 32 hours to print both shells of just the pistol. So since this was just a test to see how good my accuracy was and get a sense of how much work is involved to clean it up, I printed it in standard res, which is 0.2mm. That results in a very ugly print, but it comes out relatively fast (3.5 hours).
So back to your question:
In order to create the best print that requires the least cleanup on a curvy object like a phaser, orientation is everything. If I oriented the pistol with the inside down, then the outside curves would be parallel to the slices, and that results in big-ass gaps in what should be a smooth curve. Think of slicing a banana sideways. At 0.2mm resolution, here's what that looks like:
Very ugly
banding. As you can see, that would be extremely challenging to make smooth and even, especially for beginners.
You get much cleaner results if your curves run
perpendicular to the slices, like this, also at 0.2mm resolution:
To do that, the optimum way to orient this particular model in the printer is like this:
Unfortunately, the P2 is exactly 0.4" too long to fit inside the Makerbot's print box in this orientation, and again, since this was just a test, I decided to do the next best thing, which was to orient it like this:
This is not the optimum orientation for this shape at any resolution, precisely because it not only requires a huge amount of external support, but it also creates banding in the cradle. Even at very high resolution, this orientation still creates more work than it's worth.
So there are a number of options to make this model more printable in PLA or ABS, the two most common and accessible materials for 3D printing.
- Leave things as they are and just go with a higher resolution. This is a nonstarter for me for numerous reasons.
- Cut the model into two parts so it fits into a 6" print box in its optimum orientation. Not bad, but it still makes it hard to sand in between the ribs and the cradle. Even at 0.05mm resolution, there will still be some sanding, and I really want to make it easy.
- Break the pistol into two parts, and break off the fine-detail parts like the side and top ribs so they can be printed separately. This seems like the best way. It allows you to print the main shells in their optimum orientation, yet a lower resolution to save time and filament; you could then print the ribs at really high res in a more expensive material like the Extreme Detail stuff at Shapeways without breaking the bank.
- For those who can afford it, it's easy enough to create a set of one-piece shells for printing in higher-resolution materials on Shapeways. Right now, though, I'm limited in resources because I have a lot of cosplay-related projects going, so my cash and time have to go very far. That means I have to do this the most efficient way possible, which happens to be better for cash-strapped propaholics.
There's an important caveat, though. The maximum print size is 11" at Shapeways for PLA, but I'm not sure which way they orient it -- and their highest resolution in PLA is only 0.2mm. So that means that even on Shapeways, if you use PLA, the main shells will require sanding and maybe some putty. Again, that argues for printing those ribs separately in a better material.
My objective here is to make the "base model" as cheap and easy as possible for people to make while maintaining the highest possible accuracy. If you can afford to print in higher res with better materials and get a much cleaner print, there's nothing stopping you.
Once I've gotten it to where I'm happy enough with it to release it -- and that's not far off -- I'm not only going to post the shells for free download, but I'm also going to open-source the Blender files in various formats so that anyone with 3D experience can make improvements, which I fervently hope will broaden access to making our own replicas.